Lead Poisoning In The Bovine Animal
William C. Edwards, D. V.M. Oklahoma Animal Disease Diagnostic Laboratory Stillwater, Oklahoma 74074 and Bernard Wiedemann, D. V. M . Canadian Valley Animal Clinic El Reno, Oklahoma 73036
Lead continues to be the most commonly diagnosed cause hyperirritability or depression and convulsions. Anorexia, of poisoning in cattle. During 1979 the Oklahoma Animal diarrhea and excessive salivation are frequent Disease Diagnostic Laboratory investigated 299 cases of gastrointestinal signs 3• suspected heavy metal poisoning. Fifty-five cases were Gross and microscopic pathological changes associated confirmed as lead poisoning in cattle. with lead poisoning are minimal and diagnosis is most often The seasonal distribution involved 31 cases during the made on the basis of lead analysis of blood or tissues. The spring, 13 cases during the summer, 4 during the fall and 7 differential diagnosis must include polioencephalomalacia, during the winter months. nervous coccidiosis, insecticide poisoning, rabies, While the source of lead often remains unknown the most pseudorabies, listeriosis, cerebral edema, brain abscesses common causes encountered by our laboratory include lead and sodium ion toxicity. based paint, used crankcase oil, machinery grease, pipe joint Recommended treatment for lead poisoning includes compound and lead storage batteries. Unusual sources have parenteral administration of calcium disodium edetate. Oral included feed sacks containing 20,000 ppm lead in the administration of mineral oil, magnesium sulfate and colored printing ink, garden hose, pelleted feed and lead calcium carbonate have also been recommended. contaminated soil. Our laboratory has also investigated The toxicology section of the OADDL performed 260 I cases involving forage contaminated by industrial analytical procedures during 1979 of which 299 were heavy emissions 1• metal analyses. Blood lead levels on 27 confirmed cases Clinical signs of lead poisoning are varied and may ranged from 0.290-2.10 ppm (Table I). Most laboratories involve both the CNS and gastro-intestinal systems2• generally consider blood lead levels greater than 0.30 ppm to Common CNS signs include blindness, head bobbing, be clinically significant 3
Table I Lead Levels Associated With Clinical Lead Toxicosis in Cattle (ppm wet weight basis) No. Of TISSUE CASES MEAN RANGE
Blood 27 0.849 0.39-2.10 Kidney 27 72.84 6.20-195 Liver 19 37.5 3.99-490 Rumen Contents 3 233 80-490
150 THE BOVINE PRACTITIONER- No. 15 The average non-significant blood lead value from 51 on these three heifers were 0.03, 0.048 and 0.558 ppm. cases where lead poisoning was not confirmed was 0.066 The 15 heifers in the original treatment group were sent ppm (Table 2). home one week after their initial treatment with complete The average kidney lead level from 27 cases where lead remission of clinical signs. poisoning was confirmed was 72.84 ppm with a range of 6.20 Blood lead levels on the 3 additional heifers was to 195 ppm. determined to be 0.09, 0.30 and 0.15 ppm one week after The average non-significant lead level on 41 bovine their initial treatment and they were sent home with kidneys where lead poisoning was not diagnosed was 0.318 complete remission of clinical signs. ppm with a range of 0.02 ppm to 1.210 ppm. Case History II Case History I Six calves had died and IO were sick in a herd of 60 cows Approximately 80 head of 15 month old registered and calves. The clinical signs included bawling, circling and Holstein heifers had been exposed to ••pipe dope" left on the pica. A 3 month old heifer was submitted to the laboratory premises by an .oil well service company. There was evidence for necropsy. Water from a salt water storage tank and that four discarded buckets originally containing 25 pounds sludge pit material were also submitted for analysis. The of ••pipe dope" had been licked clean by an unknown number cattle had access to an unfenced oil production site where the of heifers. salt water tank had been recently spray painted with ••red The composition of the material was 36% grease, 30.5% lead paint". Paint chips and wet paint samples were also lead and various percentages of copper and zinc. submitted. Exposure had occured over the last two days. Forty-three The kidney lead level from the necropsied calf was 51.6 heifers with evidence of the material on their face and ppm, the sludge pit material contained 0.4 ppm lead and the muzzles were treated with I ½ gallons of mineral oil and paint samples contained 650,000 ppm lead. Paint flecks were placed under observation. Blood samples were collected noted in the rumen contents. from 15 of the animals for lead analysis. Several of the Both of these cases emphasize that several sources of lead animals were passing black tarry stools. The animals were exist around oil production sites. The availability of lead placed on grass and hay. The next day they were again containing compounds such as pipe joint compound, grease treated with mineral oil and given one pound of calcium and paint and the extreme toxicity of lead to cattle carbonate. The blood levels ranged from 0.006 to 0.420 ppm. constitutes a hazard that could perhaps be minimized by Five of the 15 animals with high levels were treated fencing oil production and drilling sites. intravenously with 200 ml calcium disodium edetate (Havidote). References Several of the animals were showing signs of mild I. Edwards, W. C. and Clay, B. R., Reclamation of Range Land depression, incoordination and drooping eyelids. The next Following a Lead Poisoning Incident in Livestock from Industrial day 3 additional heifers were showing signs of Airborne Contamination of Forage. Veterinary and Human Toxicology 19: incoordination and impaired vision. These animals were 4, 247-249 ( 1977) - 2. Buck, W. B., Toxic Materials and Neurologic Disease in Cattle JA VMA 166: 3. 222-226 ( 1975) - 3. Leary, S. L., Buck, treated three times during the day with calcium disodium W. B.. Lloyd, W. E., and Osweiler, G.D .• Epidemiology of Lead Poisoning edetate and placed under observation. The blood lead levels in Cattle. Iowa State University Veterinarian. 3: 112-117 ( 1970)
Table II Lead Levels From Cases Not Confirmed as Lead Poisoning (ppm wet weight basis)
NO.OF TISSUE CASES MEAN RANGE
Blood 51 0.066 0.02-0.28 Kidney 41 0.318 0.02-1.21 Liver 9 0.314 0.02-2.57 Rumen Contents 6 3.31 0.60-33.0
NOVEMBER, 1980 151